An X-ray computerized tomography (CT) imaging apparatus emits X-rays to an object and detects the X-rays transmitted through the object using an X-ray detector. Based on the detected X-rays, the X-ray CT imaging apparatus generates image data. The X-ray CT imaging apparatus produces and displays a three-dimensional (3D) image and internal structure of the object based on the generated image data.
FIG. 1 to FIG. 5 illustrate dental X-ray images in three dimensions (i.e., 3D image) produced and displayed by a typical image display apparatus. As shown in FIG. 1, the typical image display apparatus may produce and display a volume image of a dental arch of a patient. Based on such a volume image (i.e., 3D dental image), a user, such as a dentist, examines a tooth including a dental crown extending from a gum and a dental root covered with the gum. In order to examine the dental root with the volume image, the user manipulates the volume image as follows. The user rotates the volume image so as to see a bottom of the dental arch, as shown in FIG. 2. The user designates a region to be deleted in order to see a dental root of interest, as shown in FIG. 3. The user deletes the designated region, as shown in FIG. 4. The user rotates the volume image to see the dental roots of interest revealed after the deletion, as shown in FIG. 5.
To see the dental roots of interest with the typical display apparatus, the user generally performs at least three steps of: i) rotating the volume image, ii) designating the region to be deleted, and iii) rotating the volume image after deletion of the designated region, as described. In addition, the user should be accustomed to using the typical display apparatus. Even if the user is proficient in using the typical apparatus, it is not easy for the user to designate the region to be deleted accurately to a depth to be examined. From time to time, the user returns to and restores the entire volume image in order to change the region of interest with another region of interest. In this case, all the three steps should be performed again one after another, and which is time consuming.